The invention relates to improvements in conveyors for bulk materials in general, and more particularly to improvements in vibratory conveyors. Still more particularly, the invention relates to improvements in vibratory conveyors which can be utilized with advantage for the transport of particles of comminuted natural, artificial and/or substitute tobacco and/or other particle which do or which are likely to entrain fragments of dust or other minute solid matter.
A drawback of many presently known vibratory conveyors for particles of bulk material, including comminuted tobacco leaves, is that they are likely to segregate from the conveyed particles of bulk material large quantities of dust and/or other fragments of solid materials With attendant contamination of the surrounding atmosphere. Such conventional vibratory coveyors are particularly likely to permit and/or to cause the segregation of substantial quantities of dust and/or other relatively small impurities into the atmosphere when one or more streams of particles are caused to advance from a preceding conveying unit (such as a vibratory trough) onto or into a second conveying unit (e.g. another trough or a belt conveyor). The fragments of dust and/or other minute solid particles which become separated from the stream or streams of particulate bulk material can constitute overly comminuted portions of the particles and/or other solid substances which, at least in many instances, should not be permitted to leave the path for the conveyed particles of bulk material.
The reason for segregation of substantial quantities of dust and/or other solid impurities is that the oscillatory movements of a tray or another mobile unit of vibratory conveyor cause the development of no readily controllable flows of air which expels or entrains the impurities from the stream or streams of conveyed particles of bulk material.
The escape of thus segregated minute solid particles from the stream or streams of particulate bulk material is undesirable for the reasons of health if such particles are permitted to escape from the conveyed stream or streams in the interior of a production line for the making of cigarettes and/or other products of the tobacco processing industry. If the solid particles are to be permitted to leave the plant,they must be intercepted by suitable filters or other expensive, complex and bulky systems which must be cleaned at frequent intervals.